Furnace



y 9, 1929- I w. B. HARDWAY 1.719.885

FURNACE Filed May 16. 1922 2 Sheets-Sheet 2 ATTORNEYS INVENTOR.

Patented July 9, 1929.

UNITED STATES WILLIAM B. HARDWAY, OF CLEVELAND, OHIO.

FURNACE.

Application filed May 16, 1922. Serial No. 561,318.

The present invention, relating, as indicated, to furnaces, is more particularly directed to an improved type of furnace for burning solid fuel such as coal in a manner which is commonly looked upon as improper combustion and by utilizing the gaseous and carbon portion of the products ofs'uch combustion in such. a manner as to cause approximately perfect combustion. The results of such methods are material saving in fuel, maximum ten'lperatures when required, and a material reduction in escaping smoke. A further object of the invention is the provision of a furnace which is capable of first producing gas from the fuel used and then burning this gas in an efficient manner and With the production of a maximum efliciency and maximumtemperature at a point most desired. A further advantage of the present invention is the provision of a furnace having extreme flcxibilit that is, one in which the temperature can e raised very rapidly to meet sudden demands. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and par-- ticularly pointed out in the claims.

The annexed drawing and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawing Fig. 1 is a. side elevation of one type of my improved furnace; F 2 is a central vertiial section on the line 2 2 in Fig.

1; 3 is a section on the line 3-3 inf and Fig. 1 is a section on the line Fig. 1 4ll in Fig. 2. For convenience and clearness of descrip tion, I have illustrated my invention as cmbodied in a hot air type of furnace, but it will be readily understood that the invention may be equally well. applied to other types of furnaces.

Referring now to the figures, there is shown a hot air type of furnace consisting of a substantially cylindrical fuel burning chamber 1, provided with a grate 2, ash pit 3, and fuel and ash doors 1 and 5, res ectively. The ash pit 3 is provided with. sloped defleeting plates 6 which serve to bring the ashes onto the central part of the floor 7 for convenient removal through the door 5.

Mounted in the lower portion of the fuel chamber 1 and. extending from the level of the door 4 to the level of the grate 2, is a slightly tapered cylindrical wall 8 which is provided with several series of air inlets or ports 9. These series of air ports extend entirely around the wall 8 from the level of the grate 2 to a point slightly below the fuel door 41-. The grate is a plate which is provided with radially ar 'anged rectangular slots 10, which may be covered by a second plate 11 having similarly arranged slots 50. This plate 11 is rotatably mounted on top of the grate 2 and is movable by means of a handle 12, extending exteriorly of the chamber 1. In this way the draft through the grate may be entirely shut off when desired by moving the handle 12 a short distance in one direction to bring the slots in 'he two plates 2 and 11 outof registration. These slots are shown in register in Fig. 2 but in the normal operating condition of the furnace they will be closed.

Airjis admitted to the furnace chamber through two oppositely arranged conduits 13 and 13 which open intothe chamber 1 adjacent to the lower part of the inner wall 8 and thus allows air to be drawn through the slots 9 and over, andthus through the bed of fuel on the grate, as well as into the ash pit 3, and then upward to the fuel bed through the registering slots in. the plates 2 and 11. Mounted centrally in the furnace chamber is a burner tube 15 which is provided with a tapered portion and is supported and mounted within a second tube 16 which is formed integral with the top of the furnace chamber l. The two tubes 15 and 16 are mounted concentrically to provide a narrow space between them and air is drawn through this space, this air being admitted to thetop of this space or channel 17 by. means of conduits 18 and 18 which are shown in 2. The air passes downwardly through the channel 17 and 1s admitted in the interior of the burner tube 15 at two points, first, through a series of narrow slots 19 adjacent the. top of this tube, and second, through a second series of slots 20 which aredisposed close to the bottom of the two tubes 15 and 16. The air by being brought into the combustion tube in this manner is superheated to approximately the same temeperature as the gases which enter the bottom of the combustion tube.

the gases burn in the tube tapered, as indicated, to

Mounted above the furnace is what is generally termed an economizer 21 which is shown in plan in Fig. 3, and consists of a short straight conduit 26 which then branches to form a circular conduit 27 opening at the back of the furnace into a pipe 28 wvhich leads to the stack. The interior of the furnace chamber 1 connects with an extension 30 of the conduit 26 behind the burner tube 15, andthis connection is controlled bymeans of a damper or valve 31. The burner tube opens directly into the conduit 26 of the economizer but this connection may be closed by means of a second damper or valve 32, the two valves 31 and 32 being operated simultaneously by means of a single shaft 33 which extends through the furnace and is operated by a hand wheel 34 at the front of the furnace. The valves 31 and 32 are so mounted on this shaft that one is always closing and the other opening, and the opening of one valveautomatically closes the other.

In the ordinary operation of the furnace, fuel, such as coal, coke or the like, is charged onto the grate 2 through the fuel door 4, andjthe ordinary fuel bed will extend up and cover the air openings 9 in the wall 8. The fuel and ash doors are kept closed and-the dampers 36 and 36 which. control the air conduits 13 and 13 are normally both open. The air is thus admitted through these conduits 13 and 13 and is allowed. to pass laterally through the bed of fuel and is then drawn downwardly around the bottom edges of the burner tubes 15 and 1G. The

gases which are produced from the fuel are also drawn through the fuel bed and into the bottom of the burner tube 15. These gases are at this point mixed with superheatedair enteringjthrough the slots and 15, the tube being allow for the ex pansion of the .gases while burning. Additional air to permit complete combustionis admitted through the ports 19 adjacent to the top. of the tube and the maximum temperature is obtained at about this point.

During this operation, which is the normal operation of the furnace, the valve 32 is open and the valve 31 is closed so that all air entering the furnace chamber can discharge therefrom only by passing through the fuel bed and then into the burner tubev 15.

V Ifthe fire is to be banked, the valve 32 is closed and this operation opens the valve 31 which allows the furnace to operate in the same manner as the ordinary hot air furnace in which condition the air passes upwardly through the fuel bed and the gases 1 discharge from the furnace chamber through the valve31 into the economizer.

The present improvements, which are, of course, susceptible of incorporationin various other types of furnaces than that here shown, make possible an extremely ellici t use of the fuel. In cll'ect, my improvenrents make it possible to first treat the fuel in such a way as to produce the maximum amount of gas and then burn this gas in an efiicient type of burner to give the maximum temperature and the minimum amount of unconsumed gases, with the result that almost no smoke is produced, while the fuel does not tend to clinker and cake together as is so often the case when burning cheap fuels in the ordinary types of furnaces. Also this improvement makes it possible to burn effectively extremely cheap fuel such as slack containing a large amount of dust without preparation of the fuel.

Other modes of applying the principles of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated phere and at the other end with the combustion tube at a point adjacent to and above the opening of said tube in the fuel zone said last named conduit end being arranged parallel with said tube.

2. In a furnace, a fuel chamber provided. with a grate, means for introducing air laterally through a fuel bed on said grate, a combustion tube within the fuel chamber, said combustion tube having a contracted open end within the normal fuel zone, and an air conduit connnunicating at one end with the atmosphere and at the other end with the contracted portion of the combustion tube at a point adjacent to and above the opening of said tube in the fuel zone.

3. In a furnace, a fuel chamber having air admission ports in its walls surrounding the normal fuel zone, a grate, a combustuui tube within the fuel chamber, said combustion tube having an open end within the normal fuel zone and an air conduit communicating at one end with the atmosphere and at the other end with the combustion lltl Liz

the combustion tube at a point adjacent to and above the opening of said tube in the fuel zone.

5. In a furnace, the combination of a fuel chamber provided with a gate, a combustion tube mounted in said chamber with its lower end extending below thenormal level of the top of the fuel bed in said. chamber, said tube extending exteriorly from the upper portion of said furnace chamber, said chamber being provided with a stack opening in addition to said tube, valves respectively controlling the movement of gas through said tube and such. opening said valves being connected together and in reverse relationship and means for simultane ously operating the valves.

(3. In a fru'nace, the combination of a fuel chamber provided with a grate, an air supply conduit communicating with the atmosphere and laterally with said chamber at the level of a bed of fuel thereon, a combustion tube disposed within said fuel chamber and having its lower end open and within the normal fuel zone, and means for introducing heated air into said combustion tube at a pointadjacent its lower end.

7. In a furnace, the combination of a fuel chamber provided with a grate, an air supply conduit communicating with the atmosphere and laterally with said chamber at the level of a bed of fuel thereon, a combustion tube disposed within said fuel chamber and having its lower end open and within the normal fuel zone, and means for intr i ducing superheated air into said combustion tube at substantially the level of the fuel zone.

8. In a furnace, the combination of a fuel chamber provided with a grate, an air supply conduit communicating with the atmos phere and laterally with said chamber at the level of a bed of fuel thereon, a combustion tube disposed within said fuel. chan'ibe'r and having its lower end open and within. the normal fuel Zone, and means for progresssively introducing superheated air into said, combustion tube from various levels starting at substantially the level of the fuel.

zone.

S). In a furnace, the combination of a fuel chamber provided with a grate, an air supply conduit communicating with the atmosphere and laterally with said chamber at the level of a bed of fuel thereon, a combustion tube disposed within said fuel chamber and having its lower end open and within the normal fuel zone, and means surrounding substantially the entire length of said tube for introducing heated air into said combustion tube at two different levels.

10. In a furnace, the combination of a fuel chamber provided with a grate, an air supply conduit communicating with the atmosphere and laterally with said chamber at the level of a bed of fuel thereon, a combustion tube disposed. within said. fuel. chamber and having lower end open and within the normal fuel zone, and. a second tube disposed about said. first-named tube, said second tube communicating with the atmosphere at its upper end and with said firstnamed tube at several elevations, whereby heated air is progressively supplied to the interior of said first-nan'ied tube.

11. In. a furnace, a fuel chamber provided with a grate, a combustion tube within the fuel chamber, means for introducing air laterally through a fuel bed on said grate, said coiubiustion tube extending from the top of said chamber and having an open lower end within the normal fuel zone and an air conduit communicating through such chamber top with the atmosphere and at its lower end with the combustion tube at a point adjacent to and above the opening of said tube in the fuel. zone.

12. In a furnace, a fuel chamber provided with a grate, a combustion tube within the fuel chamber, means for introducing air latorally through a fuel bed on said grate, said combustion tube extending from the top of said chamber and having an. open lower end within the normal fuel zone, and an air-conduit surroimding substantially the entire lQDgl lI of said combustion tube, said. conduit being open at its upper end for com muni ration with the atmosphere and having communication at its lower end. with the interior of said. combustion tube.

Signed byane, this day of May, 1922.

IVILLJAll I B. HARDIVAY. 

